This invention relates generally to high-temperature industrial processes, and more particularly, to a reactor apparatus and its use in associated processes.
The production of chemicals such as hydrogen cyanide and nitric acid using a reactor has been known for some time. For example, the one-stage synthesis of hydrogen cyanide from ammonia and a hydrocarbon gas in which heat is supplied by simultaneous reactions with air in the presence of a platinum metal catalyst was disclosed by Andrussow in U.S. Pat. No. 1,934,838. Numerous modifications and improvements relating to this process have been described in other patents.
To promote efficiency, often an insulator is added to the exterior of the reactor to prevent heat loss. However, the materials comprising the reactor limit the temperatures at which it can safely operate. Sometimes a water jacket is incorporated with the reactor to prevent overheating of the reactor and a potential failure of the vessel. In the event of an interruption of service to the water jacket, temperatures may rise in the externally-insulated reactor to a level which causes the reactor or the flanged connections or other vessel-components to fail, allowing hazardous chemicals to be released into the atmosphere. The external insulator, while increasing efficiency, may also increase the likelihood of a reactor failure. There have been some attempts to insulate reactors internally with refractory materials, but typically refractory materials are very susceptible to cracking in response to thermal and mechanical shocks, which makes it difficult or impossible to start and stop the processes or remove the reactor head for maintenance without damaging the refractory. It is also extremely difficult to maintain a refractory in suspension, such as on the inside surface of a domed or conical reactor head, because refractories have relatively low tensile strength.
In addition, conventional reactor designs such as the system shown in FIG. 1 exhibit a poor flow distribution characterized by flow separations. As shown in FIG. 1, a poor flow distribution entering reactor 2 with a refractory 4 may cause an upflow on the left side of reactor 2, resulting in decomposition and soot accumulation 6 on wall 8. The jet effect of turbulent flow as shown in FIG. 1 may also result in shorter catalyst life as the flow may utilize only a limited portion of catalyst 9. Additionally, in processes containing highly flammable feed mixtures, such as oxygen-enriched HCN or oxygen enriched ammonia oxidation reactors, the flow distribution depicted in FIG. 1 creates a significant potential for flashbacks and detonations.
Further, reactor heads typically include a large weld-neck or lap joint flange for connection to a barrel, exchanger, or other apparatus which may support the reactor head. The large weld neck or lap joint flange is often very expensive to design and produce and the sealing surface must be carefully maintained to ensure a proper seal between the reactor and, for example, the barrel. The maintenance of the connection surface is very important when the reactor is in operation and contains potentially hazardous, high temperature chemicals such as the HCN present in the Andrussow process. When it becomes necessary to move the reactor head for maintenance or other reasons, operators must be extremely careful to protect the flange from damage so that the reactor can be quickly put back into service. Often an operator will simply set the reactor on a block of wood, a pad, or some other material to protect the flange; and although a block of wood or other pad may sometimes be sufficient to protect the flange from damage when properly placed, if the operator fails to block the flange and sets the reactor head directly onto typical plant grating, the weight of the reactor head on the flange surface will most likely render it unusable (if the flange surface is scratched or warped, it will not seal properly).
Finally, the physical elevation of a typical barrel upon which the reactor head rests creates a difficulty in inserting and removing items such as catalysts, distributors, supports, or any other assemblies intended to be placed inside the barrel. Often the wall of the barrel is four feet high or more, requiring an operator to climb onto a platform, over the wall, and physically enter the barrel to install or exchange the catalyst. Not only does it take time to climb into and out of the barrel, but the barrel is classified as a confined space, and entry into a confined space requires the acquisition of permits, a supply of breathing air, availability and attention of another worker to serve as hole watcher, and sometimes other expensive and time-consuming safety precautions. There is a perceived need for a design that eliminates the need for these precautions and eases the installation of the catalyst.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the issues set forth above.
In one embodiment an apparatus for a high-temperature industrial process includes at least one flanged connection, with at least one flange of the at least one flanged connection protected from mechanical damage by at least one support lug attached to the at least one flange is disclosed. The apparatus of may further include a cooling jacket attached to the at least one flange, the cooling jacket being made of a xc2xd pipe.
In another embodiment there is described an apparatus for a high-temperature industrial process including at least one flanged connection, wherein the flange is cooled by an attached xc2xd pipe cooling jacket.
In some embodiments an apparatus for a high-temperature industrial process includes an inlet piping section with a first cross-sectional dimension, a downstream process section with a second cross-sectional dimension, and an inlet transition section connecting the inlet piping section and downstream process section, with the transition section including internal insulation made of refractory ceramic fiber. The second cross-sectional dimension may be larger than the first cross-sectional dimension, and the internal insulation may form a conical interior surface. In addition, the inlet transition section may be formed to a domed geometry. The transition section may be a reactor head including a flanged connection to the downstream process section.
In some embodiments there is included one or more sight glass nozzles. A laminar velocity profile may also achieved in the downstream process section using at least one of: a sufficient length of straight pipe comprising the inlet piping section to provide laminar flow at an upstream end of the inlet transition section; at least one CRV disposed within the inlet piping section; an LAD at the upstream end of the inlet transition section; and an EHD at the upstream end of the inlet transition section.
Another embodiment for a high temperature industrial process includes a process section having a first cross-sectional dimension, outlet piping having a second cross-sectional dimension smaller than the first cross-sectional dimension; and an outlet transition section connecting the outlet piping section and the process section with an internal surface of the outlet transition section which is conical.
Still another embodiment for a high-temperature industrial process includes a reactor head having a bottom flange, and a downstream process section with a top flange where a working elevation of the downstream process section top flange is between about 2.0 and 3.5 feet.
Another embodiment of the present invention includes an inlet piping section, an inlet transition section, a process section, an outlet transition section, and an outlet piping section where internal insulation is included in one or more of the apparatus sections, and where the insulation comprises refractory ceramic fiber. In this embodiment the inlet transition section further includes a conical interior surface, and the outlet transition section further includes a conical interior surface. The apparatus may further include a flanged connection having first and second flanges between the inlet transition section and the process section and at least one of first and second flanges includes a cooling jacket attached thereto.
Also, there is described a process of producing hydrogen cyanide including the steps of: providing at least one hydrocarbon, at least one nitrogen containing gas, and at least one oxygen containing gas, reacting the at least one hydrocarbon, at least one nitrogen containing gas, and at least one oxygen containing gas in an apparatus to form hydrogen cyanide, and supplying heat by a simultaneous combustion reaction with the at least one oxygen containing gas in the apparatus; where the apparatus comprises: at least one flanged connection wherein at least one flange of the at least one flanged connection is protected from mechanical damage by at least one support lug attached to the at least one flange.
There is disclosed a process of producing hydrogen cyanide including: providing at least one hydrocarbon, at least one nitrogen containing gas, and at least one oxygen containing gas; reacting the at least one hydrocarbon, at least one nitrogen containing gas, and at least one oxygen containing gas in an apparatus to form hydrogen cyanide, and supplying heat by a simultaneous combustion reaction with the at least one oxygen containing gas in the apparatus. In this process the apparatus may include an inlet piping section with a first cross-sectional dimension, a downstream process section with a second cross-sectional dimension, an inlet transition section connecting the inlet piping section and downstream process section, where the transition section comprises internal insulation comprising refractory ceramic fiber.
In one embodiment there is disclosed an apparatus including a reactor head and internal insulation, wherein the insulation includes a refractory ceramic fiber. The reactor head is adapted to connect with a fluid stream to facilitate a chemical process. In this embodiment an angle between a conical reactor head wall and a vertical line is less than about 25xc2x0. The insulation may be held in position by at least one sleeve extending through both the conical reactor and the insulation and the insulation may be further supported by a collar extending through the reactor head inlet. The reactor head may be cone-shaped or dome shaped. The apparatus may be used for producing hydrogen cyanide or other products.
In one embodiment the apparatus further includes a cooling jacket disposed around the reactor head. The cooling jacket is made of a half-pipe attached to an outer surface of the conical reactor. It is contemplated that the apparatus may include the use of flow straightening vanes upstream of the reactor head.
In one embodiment there is disclosed a reactor head, at least one flange having a circumferential surface and a coupling surface, the coupling surface being adapted to be coupled with a mating flange in a chemical process unit, at least one support lug attached to the at least one flange and capable of supporting the reactor head, wherein the at least one support lug extends from the circumferential and coupling surfaces such that a clearance is created between the coupling surface and the support lugs. Contemplated with this embodiment may be one or more additional support lugs attached to the at least one flange and capable of supporting the reactor head. The at least two support lugs may be generally U-shaped and extend around a cooling jacket mounted to the at least one flange. The at least two support lugs may also have a generally circular hole drilled therethrough to facilitate cooling of the at least two support lugs.
In one embodiment there is disclosed a reactor head, a catalyst-bearing barrel adapted to be coupled to the reactor head, wherein the catalyst-bearing barrel exhibits a working vertical elevation between about 2.0 and about 3.5 feet and is adapted to facilitate acceptance of a catalyst or other apparatus provided by one or more operators standing outside the diameter of the barrel when the catalyst-bearing barrel is uncoupled from the reactor head. In some applications, the operators might use a hoist or other tools to assist in the installation of a catalyst or other apparatus, but the operators themselves can remain outside of the barrel.
In one embodiment there is an apparatus disclosed including a reactor head, a catalyst-bearing barrel adapted to be coupled to the reactor head, and at least one thermocouple nozzle having an internal passageway adapted to house a thermocouple or other instrumentation, mounted in the side of the catalyst-bearing barrel at a non-normal angle such that there is no direct line of sight between the catalyst elevation and the internal passageway.
There is also disclosed a process of producing hydrogen cyanide which includes providing at least one hydrocarbon, at least one nitrogen containing gas, and at least one oxygen containing gas, reacting the at least one hydrocarbon, at least one nitrogen containing gas, and at least one oxygen containing gas in a reactor to form hydrogen cyanide, and supplying heat by a simultaneous combustion reaction with the at least one oxygen containing gas in the reactor. In this process it is contemplated that the reactor includes a reactor head, a catalyst-containing barrel member, and insulation insertable into the reactor head, with the insulation comprising a refractory ceramic fiber.